Faded

I find myself neck deep in shiz-nit.

I left my '90 4-R (V6) for my brother to drive. The tank was basically empty because I didn't make to time fill it up the night before. To make a long story short, I left for work the next morning. It was cold and snowing so he went out and started it up. He forgot it was running and it idled out of gas. He went into my garage and found a gas can and poured a gallon in the tank and headed for the gas station.

Here is the problem; the gas he used was premix for my bike, it's 100LL (low lead) Avgas mixed 32:1. It started to run like it had a miss or no spark on one (or more) cylinders. After he filled it with gas he brought it back and parked it. I ran it around a little last night and it still ran like it was missing. I went through the ignition system (it was due) and installed new plugs and wires, the cap and rotor were fine. I drove it some more and it still acted the same. I had to drive it today. I've now gone 75 miles and it's almost sucked 1/2 tank of gas. The engine light is on and I'm guessing it's going to say bad O2. I know the lead in the gas harms catalytic converters and O2 sensors, hence the light. I'm wondering if the cat is clogged or maybe somehow the fuel filter is blocked although it seems like it's getting plenty of gas. Like I said, it drives like there is a miss but the ignition checks out so I'm thinking it's something else.

Please help, I have one week to fix this. If you have any ideas that I could try please let me know. I am so bummed about this and it couldn't have come at a worse time.

Thanks in advance,
Andrew

amusement

>Drain the tank.
>Change your spark plugs.
>Change your oil and oil filter
>Change your fuel filter
>Get a 5 gallon can of gas 87 octane.
>Put about 1/2 of fuel injection cleaner
bottle in it.

PRAY!!!!!!!

find a ODB I reader or search yota for locating the ECM codes on your 90 4 runner.

and PRAY some more!!!!

Cross your fingers and pull out your rabbit's lucky foot and PRAY some more.

I ain't in to relgion but, you should start.

Rayday81

Oh man, I feel sick to my stomach hearing this. I really hope it all works out for you man, this is some terrible ˟˟˟˟˟ to happen especially since it seems like it was really just an accident, as your brother probably didn't know that it 100LL gas in the gas can. Damn :pat:

Faded

Yea, it makes me feel sick too. I just hope I can fix it with minimal effort. It was purely an accident and I'm partly to blame. I don't have any of my gas cans marked so it's hard to tell what is what. I'll be pulling the codes tonight to see what they say. I can only hope I can somehow fix it.

Faded

bump...:cry:

Faded

Okay, here is an update.

I went to the local muffler shop this morning and they pressure tested the cat. converter. Kinda neat really, they drilled two small holes in the cat's piping, before and after the cat. Then they stick a pressure gauge against the hole and rev her up. When they're done they just spot weld the holes closed. Took about 10 minutes and was only $10.

Anyway, the cat tested fine, for now. They thought it was a fuel delivery problem, and are probably correct. She's running way rich, 80 miles to a half tank of gas. I pulled the codes after I got back from the muffler shop:

25 - AIR/FUEL RATIO LEAN INDICATOR--LEAN SIGNAL SENT TO ECU FROM O2 SENSOR

AND

26 - AIR/FUEL RATIO RICH INDICATOR


Kinda contradictory? I called around to some EFI shops but they are all closed today. Does anyone have any other ideas with this new information???

Thanks in advance,
Andrew

tenfourtyeight

Bump.

Sorry to hear about this. I too would feel sick to my stomach.

MTL_4runner

I would guess he ruined your O2 sensor.
Only other thing could be the AFM but bad gas would not affect that at all.

Reason why it is running like crap is the O2 provides feedback to the computer. Without it the truck will run very rich to ensure no damage occurs to the engine while in this condition. You might want to adjust your AFM anyway to help your efficiency while in this condition until you can get a new O2 sensor.

diverjeff200

Andrew,

Sorry to hear about your misfortune but is sounds like luck may be smiling on you. I have just gone out and marked all of my different fuel containers, eg. weedeater, chain saw, mower, etc.

One question though...

When you were talking about pulling the codes, do you have a code reader or is there a way to pull the codes without the reader? I have a 95 SR5 4x4.

Thanks and good luck!!

DJ

Faded

I don't think it's the O2 sensor. I had a bad 02 in my truck and my mileage went down 2-3mpg. As of today it's down around 9mpg, about half of what it usually gets. It is getting so much raw gas that it barely runs. Also, the MIL would have signaled a code 21 (I think), which is a bad 02 sensor.

I took it into a FI shop today to see if they could diagnose it because I really don't have the time. I'll post if they figure out what it was.

As for pulling codes, on my 4-R there is a gray box by the under hood fuse box (near the battery). If you open the lid it lists the pinouts. To get the check engine light to blink the codes insert a jumper (piece of wire) between terminals E1 and TE1. After this, climb in the cab and turn your key to the on position. The check engine light will start blinking the codes. There is a 4.5 second delay between single digit codes and a 2.5 second delay between two digit codes.

Thanks,
Andrew

My99

I'd say O2 sensor as well. Just because you saw 2mpg last time when you replaced it, doesn't mean it can't be that. Think about what else it could be? Either the MAS has gone crazy, which wouldn't make any sense with the bad gas theory, or the O2 sensor, which reads FROM THE EXHAUST SIDE has gone bad which is where the lead would have ended up. WHen I first started reading this, I wanted to say that it's the catalytic converter. AFter driving the truck hard at night, crawl under there and see if it's glowing red. I don't know what shop you took your truck to to have the cat tested, but if you trust them, maybe it's not the cat. However, this would be by first guess. I used to run a mix of leaded fuel and unleaded fuel in my race car back in the day and didn't ruin my O2 sensor. Another tip is that if you're very machanic savy, you can take a torch and burn off the lead deposits on your O2 sensor and they'll often start working correctly again.

Just a thought. Let us know what you find out. BTW, I assume you've gotten all of the oil/gas mix out of the tank and are running clean 87 octane now. If you're still running the bad gas, you can expect ridiculous mileage like that. I wouldn't think it would hurt your truck much at all, lead is just bad for catalytic converters and O2 sensors, and oil will just make your truck run like an old domestic.

MTL_4runner

First, I would guess you have not dropped the tank and emptied all the fuel (make sure to get it all out).....do so or you will continue to damage sensors. Second, your bad mileage is likely coming from the bad fuel and O2 sensor. If the sensor is out of whack it will continue to give input to the computer to richen the mixture because it may be distorting the output voltage of the sensor. Combine this with the bad fuel and there is not way for the vehicle to run correctly. Try actually unplugging the O2 sensor and se if that helps you mileage. If so then the sensor is definately bad. When unplugged the vehicle will then rely on the AFM and TPS to figure out the fuel ratio.

There is really nothing else the leaded fuel can damage that will make it run that badly.

Faded

Kyle and Jamie,

I appreciate your thoughts. I really don't think it's the O2 sensor. Even if it was whack and distorting the voltage signal out the ECU only gives it a certain margin of error before it throws out the signal completely. At this time it will illuminate the CEL telling you something is wrong with the O2. Since this is not the case I overlooked the O2.

I have also used a torch before in the past to revive O2 sensors, plugs, etc.

I did drive my truck hard and check the cat. It was not glowing red.

I have done this before with no ill effects. That is why it puzzles me this time.

Your guess would be correct. The gas isn't "bad". Like My99 I have mixed leaded and unleaded gas before without negative effects. Only 1 gallon of the "bad" gas was put in and then it was dilluted by another 16 gallons of regular gas. A far cry from the 50/50 mixed that I've used in other vehicles without problems (and the race gas I used contained larger amounts of lead than the 100LL that went into my 4-R).

My99

I want to clarify something. You said it was a mix of 32:1... I assume it was a two stroke mix, of oil. If this is right, then my assumption is correct. Now, I should mention that I did run leaded gas in a car that had O2 sensors but had NO catalytic converter. I honestly can think of nothing else but an O2 sensor or a catlytic converter that leaded gas would affect. I wish you could read the O2 voltage and see what it actually is, I'm betting the computer is dumping a lot more fuel than you need and that's why you're getting bad gas mileage. How's the power? I would expect it to decrease a good amount if this is the case.

MTL_4runner

I agree with what he said.

Personally I think it is foolish not to dump the bad gas anyway in an effort to trobleshoot the problem, but it is your truck and I do wish you the best with it.

BTW the ECU only throws out the O2 voltage if it is out of spec (ie greater than a certain voltage).....not if it is just giving false readings (ie the reading is just skewed to run very rich). This condition would also NOT give you a CEL. Just something to think about.

Seriously, try unplugging your O2 sensor(s) and see if that helps.

amusement

Faded have you completed any of the activies listed above?
If not, then why?

Faded

Basically all but the drain your tank part.

Yes, it was gas mixed with oil. It ran like there was a miss, or a rich bog that never goes away.

I really do appreciate your comments. I know you all probably think I'm ignorant or stubborn as well, but I had my reasons for ruling out certain things. Anyway, it turns out that the injectors on cylinder #1 and #5 were hanging open causing rich running at all times. It was just debris and everthing was good after cleaning the injectors, fuel lines, rails.... Just driving it back there was a noticable difference in seat-of-the-pants power, smoothness @ idle, etc. compared to before I had these problems. There isn't an explainable solution, just my luck that brought the circumstances together.

Thanks again for your replies, I didn't mean to be an #@$. The good news is that she's back, and better than before.

My99

I didn't think you were being controversial. Advice is advice, take it or leave it. I'm the same as you, sometimes I think no it's not that, sometimes otherwise. I'm wondering what clogged the fuel injectors though. I wouldn't think oil would do it. Perhaps when your brother let it idle out of gas some sediment at the bottom of the tank made it through the filter and clogged up the fuel injectors. Anyway, glad you got it sorted out.

Faded

Thanks, this is exactly what I thought, hence the total cleaning of the fuel delivery system. Thanks for understanding, and for the help.